Vinyl esters, prepared by the interaction of epoxide resins having terminal epoxide groups with low molecular weight .alpha., .beta.-unsaturated organic acids, or variants thereof have been widely used in structural applications with glass reinforcement, the latter being commonly in the form of cloth or fibers. In such applications, the glass is impregnated with the resin and holds the resin in place while the resin is cured or hardened. Such compositions have exhibited excellent resistance to corrosion. However, their inherent brittleness frequently makes them generally unfit for use for certain applications, such as for pipe linings. When such compositions are employed in pipe linings, the inner barrier layers of the linings are very rich in the unreinforced resin, and only enough glass or other veil material is included to support the syrupy resin as the latter hardens. Excessive stresses, such as those resulting from accidental impact, improper installation, mechanical fatigue and thermal shock, can cause cracking or crazing of the inner barrier layer, reducing its fitness for its intended function and leading to possible ultimate pipe failure.